Method for managing image data and motor vehicle lighting device

Abstract

The present invention provides a method for managing image data in a motor vehicle lighting device (10). The method comprises the following steps: providing an image pattern (1); dividing the image pattern (1) into pixel rows or pixel columns (2); calculating a first gradient value related to the relationship between the value of a first pixel and the values of adjacent pixels; for each pixel, checking whether the difference between the corresponding gradient value and the first gradient satisfies one of a first condition or a second condition; defining a linear segment; compressing the values of the linear segment; and sending the compressed data to an optical module. The present invention also provides a motor vehicle lighting device (10) for performing the steps of such a method.

Description

Field of the Invention

[0001] The present invention relates to the field of motor vehicle lighting devices, and more particularly to the management of electronic data relating to the control of a lighting source. Background Art

[0002] Current lighting devices include an increasing number of light sources that must be controlled to provide adaptive lighting functions.

[0003] This number of light sources involves a large amount of data that must be managed by a control unit. The CAN protocol is often used, in some of its variants (CAN-FD being one of the most commonly used protocols), for transmitting data between the PCM and the optical module. However, some vehicle manufacturers have decided to limit the bandwidth of the CAN protocol, and this affects management operations, which typically require approximately 5 Mbps. The PCM is the Pixel Control Module, which is a control unit configured to manage the pixel pattern of each optical module. Since each headlight can include different optical modules arranged to manage at least one lighting function partially or entirely, it is important that they be controlled by a single control unit such as the PCM.

[0004] Current compression methods are not very effective for the high beam pattern, and this discounts the bandwidth reduction required by vehicle manufacturers.

[0005] This problem is even more severe for modern high-resolution modules, where the amount of information is much higher and the bandwidth limitations have not increased.

[0006] A solution to this problem is sought. Summary of the Invention

[0007] The present invention provides a solution to these problems by means of a method for managing image data in a motor vehicle lighting device, the method comprising the following steps:

[0008] - Providing an image pattern including a plurality of pixels, wherein each pixel is characterized by a numerical value related to the luminous intensity of the pixel;

[0009] - Dividing the image pattern into pixel rows or pixel columns, thereby creating a plurality of row patterns;

[0010] - Selecting a first pixel of a row pattern among the row patterns, and calculating a first gradient value related to the relationship between the numerical value of the first pixel and the numerical values of adjacent pixels;

[0011] - Calculating a corresponding gradient value for each pixel;

[0012] - For each pixel, check whether the difference between the corresponding gradient value and the first gradient satisfies one of a first condition or a second condition;

[0013] - Repeat the previous step until an end pixel is found, at which the difference between the corresponding gradient and the first gradient does not satisfy the first condition;

[0014] - Define a linear segment between the first pixel and the end pixel;

[0015] - Select a different first pixel and repeat the steps of calculating the first gradient value, calculating the corresponding gradient value, checking for satisfaction of the first and second conditions, finding the end pixel, and defining the linear segment until segments are defined for the entire line pattern;

[0016] - Compress the data of the linear segment; and

[0017] - Send the compressed data to the optical module of the lighting device.

[0018] The method aims to manage the image data exchanged between the control unit and the optical module. The control unit is responsible for calculating the image pattern and compressing the data and can be located anywhere in the motor vehicle, not necessarily physically inside the lighting device. The lighting module aims to provide a light pattern for lighting or signaling and is located inside the lighting device.

[0019] The main advantage of the method is the improvement in the compression rate, which is due to the optimization in the extension of the linear segments. The above method provides a fast and reliable way to extend the segments until the conditions are not satisfied, thereby providing less data compared to the original pixels replaced by the linear segments, especially when the image pattern refers to a high beam pattern. The pseudo-Gaussian shape of the line pattern also helps to improve the compression rate because some parts of the line pattern can be replaced by a linear approximation without significant loss in data.

[0020] In some specific embodiments, the light pixels of the image pattern are gray-scale pixels, and more specifically, the luminous intensity of each pixel is according to a scale from 0 to 255.

[0021] The optical module typically defines the light pattern in gray scale, where the luminous intensity is graded from 0 to 255. This is a way to quantify the light pattern so that the light pattern can be converted into light data and then transmitted and managed by the control unit of the vehicle.

[0022] In some specific embodiments, the first condition includes: defining a first threshold; and checking whether the absolute value of the difference between the corresponding gradient value and the first gradient is less than or equal to the first threshold.

[0023] For each pixel, the first condition is checked. The first condition compares the corresponding gradient value calculated for each pixel with the first gradient value calculated for the first pixel of the segment. When the amount by which the corresponding gradient value deviates from the first gradient value is greater than a first threshold, the segment will terminate at the end pixel.

[0024] In some specific embodiments, the second condition includes: defining a second threshold; and checking whether the absolute value of the corresponding gradient value is less than or equal to the second threshold.

[0025] For each pixel, the second condition is checked. The second condition only verifies that the absolute value of the corresponding gradient value calculated for each pixel is below the second threshold. This is used to detect sudden high gradients.

[0026] In some specific embodiments, the method further includes the step of decompressing the compressed data.

[0027] This step is convenient when the optical module is to project the original image.

[0028] In some specific embodiments, the compressed data is only related to a specific part of the image pattern.

[0029] This cropping step is useful when most of the image is completely dark, such that the compression stage only focuses on the part containing representative values.

[0030] In a second aspect of the invention, the invention provides an illumination device, comprising

[0031] - an optical module including a plurality of light sources; and

[0032] - a control unit for performing the steps of the method according to the first aspect of the invention.

[0033] The illumination device is capable of operating with a lower bandwidth than conventional illumination devices.

[0034] In some specific embodiments, the optical module further includes a processor unit configured to decompress the compressed data.

[0035] With the decompression stage in a suitable optical module, the bandwidth will narrow until the module itself.

[0036] In some specific embodiments, the light sources are solid-state light sources, such as LEDs.

[0037] The term "solid state" refers to light emitted by solid state electroluminescence, which uses semiconductors to convert electricity into light. Compared with incandescent lighting, solid state lighting produces visible light with reduced heat generation and lower energy consumption. Compared with fragile glass tubes / bulbs and slender filaments, solid state electronic lighting devices, which are generally of smaller mass, provide greater resistance to shock and vibration. They also eliminate filament evaporation, potentially increasing the lifespan of the lighting device. Some examples of these types of lighting include semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or polymer light-emitting diodes (PLEDs) as the light source, rather than electric filaments, plasmas, or gases.

[0038] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall be construed in accordance with the conventions of the relevant art. It will be further understood that commonly used terms shall also be construed in accordance with the conventions of the relevant art, rather than in an idealized or overly formal sense, unless expressly so defined herein.

[0039] In this document, the term "comprising" and its derivatives (such as "including", etc.) shall not be construed in an exclusive sense, that is, these terms shall not be interpreted as precluding the possibility that the described and defined content may include other elements, steps, etc. Description of the Drawings

[0040] To complete the description and to better understand the present invention, a set of drawings is provided. The drawings form part of the specification and illustrate embodiments of the present invention, which should not be construed as limiting the scope of the present invention, but only as examples of how the present invention may be implemented. The drawings include the following figures:

[0041] Figure 1 shows a first image of the photometric measurement of a high beam module projected by a motor vehicle lighting device according to the present invention.

[0042] Figure 2 shows a part of a pixel matrix representing an example of photometric measurement.

[0043] Figure 3 shows a representation of a line pattern of a method according to the present invention.

[0044] Figure 4 shows a representation of some of the steps in a method according to the present invention.

[0045] Figure 5 shows the result of a linearization step when using the method according to the present invention.

[0046] Figure 6 shows a motor vehicle lighting device according to the present invention. ​​​​​​

[0047] In these figures, the following reference numerals are used:

[0048] 1 Image pattern

[0049] 2 Line pattern

[0050] 3 Pixels of the image pattern

[0051] 4 Optical module

[0052] 5 LED

[0053] 6 Control unit

[0054] 7 Processor unit

[0055] 10 Motor vehicle lighting device

[0056] 100 Motor vehicle. Detailed description of the specific embodiments

[0057] The example embodiments are described in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes described herein. It is important to understand that the embodiments can be provided in many alternative forms and should not be construed as limited to the examples set forth herein.

[0058] Accordingly, while the embodiments can be modified in various different ways and can take various different alternative forms, specific embodiments thereof are shown in the drawings and are described in detail below as examples. There is no intention to limit the specific forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included.

[0059] Figure 1 A first image of the photometric measurement of a high beam module projected by a motor vehicle lighting device according to the present invention is shown.

[0060] This first image can be divided into pixels, and each pixel can be characterized by the luminous intensity of the pixel, with a scale of luminous intensity ranging from 0 corresponding to black to 255 corresponding to white.

[0061] Figure 2 A part of such a pixel matrix, referred to as image pattern 1, is shown. Each pixel 3 of this image pattern 1 is characterized by a number according to the aforementioned scale. Compression of this image pattern 1 by commercially available software products will provide a compression ratio of less than 50%, which is unacceptable to some automobile manufacturers.

[0062] In this image, the pixels are divided into row patterns 2. Each pattern includes a data string with numbers between 0 and 255, depending on the luminous intensity of the associated pixel. Obviously, the numerical values of these pixels are simplified examples, only chosen for better understanding of the present invention, and these numerical values of the pixels do not correspond to Figure 1 the luminous intensity of the light pattern.

[0063] Figure 3 The first row of the previous figure is represented. There are 18 numbered pixels, each pixel having a numerical value representing the luminous intensity of each pixel.

[0064] A specific embodiment of the method of the present invention will include the step of calculating the gradient of each pixel of the row pattern.

[0065] Figure 4 This gradient pattern is shown. For each pixel, the numerical value of the luminous intensity has been replaced by the corresponding gradient value with respect to the previous figure.

[0066] The first pixel serves as the starting point of the first linear segment. Then, for each pixel, two conditions are checked. If the pixel meets these two conditions, then the pixel belongs to the same linear segment. However, if the pixel does not meet either of these two conditions, then the pixel is set as the end pixel of the segment, and a different segment starts at the next pixel.

[0067] Following Figure 3 the example of

[0068] the first linear segment will start at the first pixel, which has a gradient value of 3. Set the first threshold at 4 and the second threshold at 50.

[0069] Therefore, for each pixel, the first condition will be that the difference between the corresponding gradient and the first gradient (which is 3) is less than or equal to 5.

[0070] Furthermore, the second condition will be that the gradient is less than 50.

[0071] With these two conditions specified, the first segment will end at the fourth pixel because the difference between the gradient of the fourth pixel and the first gradient value is greater than 5.

[0072] Therefore, the second segment will start at the fifth pixel. This second segment will end at the eighth pixel because the sixth and seventh pixels meet the two conditions, while the eighth pixel does not meet either the first condition or the second condition.

[0073] The third segment will start at the ninth pixel and will end at the tenth pixel because the tenth pixel does not meet the first condition or the second condition.

[0074] Each linear segment will have the gradient of the first pixel of each segment to store the data in the system. Thus, the luminous intensity values in the linearized version will be slightly different from the original values.

[0075] Figure 5 The linearized values representing each pixel, with each segment represented by a different color.

[0076] For each pixel, the "original" line represents the original luminous intensity value, and the "linearized" line shows the result of the linearized segment intensity values. Each segment has a constant gradient, which is given by the gradient of the first pixel of each segment.

[0077] Obviously, in a line pattern with real data, the number of segments will be significantly lower than the number of pixels, and this example is only intended to address all cases that the method may face.

[0078] Figure 6 Shows a motor vehicle lighting device according to the invention, which lighting device comprises:

[0079] - A light module 4, which light module 4 comprises a plurality of LEDs 5;

[0080] - A control unit 6, which control unit 6 is used to perform the compression steps described in the previous figures to generate compressed data; and

[0081] - A processor unit 7, which processor unit 7 is configured to decompress the compressed data, and which processor unit is located in the light module 4.

[0082] The light module will achieve a high-quality projection with an improved transmission bandwidth.

Claims

1. A method for managing image data in a motor vehicle lighting device (10), the method comprising the following steps: - Providing an image pattern (1) comprising a plurality of pixels (3), wherein each pixel is characterized by a numerical value related to the luminous intensity of the pixel (3); - Dividing the image pattern (1) into pixel rows or pixel columns, thereby creating a plurality of row patterns (2); - Selecting a first pixel of a row pattern among the row patterns (2), and calculating a first gradient value related to the relationship between the numerical value of the first pixel and the numerical values of adjacent pixels; - Calculating a corresponding gradient value for each pixel; - For each pixel, checking whether the difference between the corresponding gradient value and the first gradient satisfies one of a first condition or a second condition; - Repeating the previous step until an end pixel is found, at which the difference between the corresponding gradient and the first gradient does not satisfy the first condition; - Defining a linear segment between the first pixel and the end pixel; - Selecting a different first pixel, and repeating the steps of calculating the first gradient value, calculating the corresponding gradient value, checking for satisfaction of the first condition and the second condition, finding the end pixel, and defining the linear segment until segments are defined for the entire row pattern (2); - Compressing the data of the linear segments; and - Sending the compressed data to the light module of the lighting device.

2. The method according to claim 1, wherein, The pixels (3) of the image pattern (1) are gray-scale pixels, and more specifically, the luminous intensity of each pixel (3) is characterized by a number according to a scale from 0 to 255.

3. The method according to any one of the preceding claims, wherein, The first condition includes: defining a first threshold; and checking whether the absolute value of the difference between the corresponding gradient value and the first gradient is less than or equal to the first threshold.

4. The method according to claim 1 or 2, wherein The second condition includes: defining a second threshold; and checking whether the absolute value of the corresponding gradient value is less than or equal to the second threshold.

5. The method according to claim 1 or 2, wherein The compressed data is only related to a specific part of the image pattern (1).

6. The method according to claim 1 or 2, further comprising the step of decompressing the compressed data.

7. A motor vehicle lighting device (10), comprising: - A light module (4), the light module (4) comprising a plurality of light sources (5); and - A control unit (6) configured to perform the steps of the method according to any one of claims 1 to 5.

8. The motor vehicle lighting device (10) according to claim 7, wherein, The light module (4) further comprises a processor unit (7) configured to decompress the compressed data.

9. The motor vehicle lighting device (10) according to claim 7 or 8, wherein, The light sources (5) are solid-state light sources.

10. The motor vehicle lighting device (10) according to claim 9, wherein, The light sources (5) are LEDs.

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